Heat exchanger for an oxygenator and method for producing such a heat exchanger

Abstract

A heat exchanger for an oxygenator comprises multiple tube sections, each having a longitudinal tube axis, wherein the tube sections are disposed as a bundle having a longitudinal bundle axis, and the tube sections are connected to each other in at least one connecting section of the bundle by joining by way of chemical and/or physical bonded joints. A method for producing the heat exchanger is also provided.

Claims

1. A method for producing a heat exchanger for an oxygenator, comprising: providing multiple tube sections, each having a longitudinal tube axis; disposing the tube sections to form a bundle having a longitudinal bundle axis and opposed ends, wherein the longitudinal tube axes are oriented parallel to each other; joining the tube sections to each other by way of at least one of chemical and physical bonded joints and thus building at least one connecting section of the bundle, wherein the joined tube sections and the at least one connecting section establish a prefabricated bundle which is dimensionally stable in itself and which is formed by adhesive bonding of the individual tube sections to each other, and inserting the prefabricated bundle into a housing, wherein the bundle is inserted into the housing in such a way that a connecting section that is disposed at each bundle end is disposed at least sectionally outside the housing, wherein the bundle is severed at the at least one connecting section, wherein the portions of the connecting sections protruding over the housing are severed.

2. The method according to claim 1, further comprising twisting the bundle about the longitudinal bundle axis after the tube sections have been connected.

3. The method according to claim 2, wherein twisting of the bundle about the longitudinal bundle axis disposes the longitudinal tube axes of the tubes of the bundle at an angle relative to the longitudinal bundle axis.

4. The method according to claim 1, wherein the housing into which the bundle is inserted is tubular.

5. The method according to claim 1, further comprising compressing the bundle along the longitudinal bundle axis after the tube sections have been connected to impart a curvature to the tube sections of the bundle.

6. The method according the claim 1, wherein the bundle is substantially cylindrical.

7. The method according to claim 1, wherein the tube sections are exclusively connected to each other by adhesive bonding.

8. The method according to claim 1, wherein the bundle is held in the housing by a press fit in the region of the connecting sections.

9. A method for producing a heat exchanger for an oxygenator, comprising: providing multiple tube sections, each having a longitudinal tube axis; disposing the tube sections to form a bundle having a longitudinal bundle axis, wherein the longitudinal tube axes are oriented parallel to each other; and joining the tube sections to each other by way of at least one of chemical and physical bonded joints and thus building at least one connecting section of the bundle, wherein the joined tube sections form an independent, prefabricated bundle that is dimensionally stable in itself before the prefabricated bundle is inserted into the housing, wherein the dimensionally stable bundle is formed by adhesive bonding of the individual tube sections to each other, and wherein a cross-sectional surface of the bundle is oriented perpendicularly to the longitudinal bundle axis is circular.

10. The method according to claim 9, wherein the dimensionally stable bundle is inserted into the housing and connected to the housing.

11. The method according to claim 10, wherein the inserted bundle is subsequently joined in the housing of the heat exchanger.

12. The method according to claim 9, wherein the tube sections are exclusively connected to each other by adhesive bonding.

13. A method for producing a heat exchanger for an oxygenator, comprising: providing multiple tube sections, each having a longitudinal tube axis; disposing the tube sections to form a bundle having a longitudinal bundle axis, wherein the longitudinal tube axes are oriented parallel to each other; joining the tube sections to each other by way of at least one of chemical and physical bonded joints and thus building at least one connecting section of the bundle, wherein the joined tube sections and the at least one connecting section establish a prefabricated bundle which is dimensionally stable in itself and which is formed by adhesive bonding of the individual tube sections to each other, inserting the prefabricated bundle into a housing, adhesively bonding the at least one connecting section via an outer lateral surface to an inner side of the housing, wherein the adhesive used for connecting the at least one connecting section to the housing is the same adhesive as used for connecting the individual tube sections to each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention are described in more detail hereafter based on the drawing. In the drawings:

(2) FIG. 1 is a side view of an inventive heat exchanger according to a first embodiment;

(3) FIG. 2 is a sectional illustration according to line II-II from FIG. 1;

(4) FIG. 3 is a view of a bundle in a housing corresponding to FIG. 1;

(5) FIG. 4 is a view of a heat exchanger according to a further embodiment corresponding to FIG. 1; and

(6) FIG. 5 is an enlarged detailed illustration of tube sections of the bundle corresponding to FIG. 2.

DETAILED DESCRIPTION OF AT LEAST ONE PREFERRED EMBODIMENT

(7) A heat exchanger 1 shown in FIGS. 1 to 3 comprises multiple tube sections 3, each having a longitudinal tube axis 2. The tube sections 3 are made of plastic material, and more particularly of polyurethane (PUR). Other plastic materials can also be used to produce the tube sections 3, such as polyester, in particular polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polyamides and co-polymers or polyurethanes and copolymers, in particular polyether polyurethane or polyester polyurethane.

(8) According to the shown exemplary embodiment, the tube sections 3 are disposed to form a bundle 4, which has a longitudinal bundle axis 5. The tube sections 3 are disposed in each case in such a way that the longitudinal tube axes 2 thereof are in each case oriented parallel to each other and parallel to the longitudinal bundle axis 5.

(9) The tube sections 3 are connected to each other in two two connecting sections 6, which are in each case disposed on bundle ends 7, by adhesive bonding, which is to say by joining by way of chemical and/or physical bonded joints. According to the shown embodiment, the tube sections 3 are exclusively connected by an adhesive 8 in the respective connecting section 6. This means that the individual tube sections 3 are directly connected to each other.

(10) The bundle 4 has a substantially cylindrical basic shape. A cross-sectional surface oriented perpendicularly to the longitudinal bundle axis 5 is circular. However, it is essentially also conceivable to use other basic shapes for the bundle 4. The connecting sections 6 likewise have a cylindrical shape and have a height H that is oriented along the longitudinal bundle axis 5. According to the shown exemplary embodiment, the height H is 5 mm.

(11) The heat exchanger 1 has a length L, which is delimited by the two connecting sections 6 disposed opposite each other at the bundle ends 7. Within the length L, the heat exchange takes place between the heat exchanger medium, and more particularly water, and the blood flowing between the tube sections, and more particularly in a manner that is directed counter to the flow direction of the heat exchanger medium. According to the shown exemplary embodiment, the length L is approximately 170 mm. The length L of the heat exchanger 1, the number of tube sections 3 disposed to form the bundle 4, the respective inside tube diameter of the tube sections 3, and the respective wall thickness of the tube sections 3 are selected in accordance with the requirements in regard to the heat exchanger 1. According to the detailed illustration of the exemplary embodiment of FIG. 5, an inside diameter d.sub.i=0.67 mm, an outside diameter d.sub.a=0.79 mm, and a tube wall thickness d.sub.s=0.06 mm. In particular the number of tube sections 3 that are used can vary as a function of the patient's size, which is to say the volume of the blood to be circulated.

(12) The bundle 4 has a constant cross-sectional surface along the longitudinal bundle axis 5. In particular, the respective cross-sectional surfaces at the two bundle ends 7 are identical in size. A perpendicular distance D between outer walls 10 of two neighboring tube sections 3 is no more than 200 m. The distance D is in particular no more than 100 m. It is thus assured that the tube sections 3 are combined with greater density to form the bundle 4.

(13) As is shown in FIG. 3, the bundle 4 is disposed at least sectionally in a housing 9. The connecting sections 6 each protrude half way, which is to say with approximately 50% of the height H, from the housing 9. This means that an inner section having a length L.sub.i of the connecting section 6 is disposed inside the housing 9. On the inner region of the connecting sections 6, which in particular has a cylindrical design, these are adhesively bonded via the outer lateral cylinder surface thereof to an inner side of the housing 9. For this purpose, in particular the same adhesive 8 is used as for connecting the individual tube sections 3. The length L.sub.i is approximately 50% of the height H of the connecting section 6, which is to say approximately 2.5 mm, and thereby assures secure connection of the bundle 4 in the housing 9.

(14) Based on the illustration of FIG. 4, a further embodiment of a heat exchanger will be described hereafter. Identical parts, which were already described based on FIGS. 1 to 3, are denoted by identical reference numerals and will not be described again in detail.

(15) The essential difference of the heat exchanger 1 according to the further embodiment is that the tube sections 3 are disposed in such a way that the longitudinal tube axes 2 form an angle a with the longitudinal bundle axis 5 which in particular is greater than 10, in particular greater than 20, and in particular greater than 30. It is thus assured that the flow behavior of the blood through the heat exchanger 1 is improved. In addition or as an alternative, it is possible for the tube sections 3 to be disposed in the bundle 4 in such a way that the longitudinal tube axes 2 are at least sectionally disposed in a non-linear fashion, and more particularly in a curved fashion relative to the longitudinal bundle axis 5.

(16) A method for producing a heat exchanger 1 according to the invention will be described in more detail hereafter. First, multiple tube sections 3 having preferably identical lengths are provided. Depending on the required heat exchanger capacity, the number and length of the tube sections 3 can vary. The tube sections 3 are disposed in a sleeve-shaped mounting, in particular a cylindrical pipe, to form a bundle 4, wherein the longitudinal tube axes 2 of the tube sections 3 are preferably oriented parallel to the longitudinal bundle axis 5. Thereafter, the tube sections 3 are connected in the at least one connecting section 6, and more particularly in two connecting sections 6 that are disposed in each case at one bundle end 7 of the bundle 4. The tube sections 3 are connected to each other by adhesive bonding, in particular by way of acrylic resin. By adhesively bonding the tube sections 3 to each other, the tube ends are hermetically sealed and thus protected from internal contamination. Thereafter, the adhesively bonded bundle 4 is inserted into the housing 9, wherein each of the two connecting sections 6 protrudes at the end face from the tubular housing 9. So as to assure compression and/or curvature of the tube sections 3 of the bundle 4, initially a first connecting section 6 is adhesively bonded to the section of the connecting section 6 remaining in the housing 9 on an outer lateral cylinder surface in the housing 9. As a result, the bundle 4 is closed off and sealed in the housing 9. The adhesive surface is large and assures secure attachment of the first connecting section 6 in the housing. The bundle 4 can now be twisted about the longitudinal bundle axis 5, so that the longitudinal tube axes 3 of the tube sections 3 are disposed at an angle a relative to the longitudinal bundle axis 5. In addition or as an alternative, it is possible to compress the bundle 4 along the longitudinal bundle axis 5, so that the tube sections 3 at least sectionally have a curvature. For this purpose, the second, free connecting section 6 is compressed and/or twisted in relation to the first connecting section that is fixed in the housing 9. The free connecting section 6 is held on the outer section protruding from the housing by way of a gripping tool. As soon as the second connecting section 6 has been brought into a desired position, it can likewise be adhesively bonded along an outer lateral cylinder surface to an inner side of the housing 9. As an alternative, however, it is also possible to achieve positioning of the connecting sections 6 with respect to each other by positioning the two connecting sections 6 relative to each other so as to be freely movable in relation to the housing 9 by way of a respective gripping tool, and by subsequently adhesively bonding them in the housing 9. After the bundle 4 has been adhesively bonded to the housing 9, the portions of the connecting sections 6 protruding over the housing 9 are severed. This re-opens the ends of the tube sections 3.

(17) It is also conceivable for the bundle 4 to be held in the housing by a press fit in the region of the connecting sections 6. The press fit is assured by an outside diameter of the connecting sections 6 being greater than an inside diameter of the housing 9. In this case, the adhesive bonding of the bundle 4 in the housing 9 can be dispensed with. The oversized dimension of the connecting sections 6 required for this purpose can be established based on the pressing force that is to be achieved and the material properties of the connecting section 6 and of the housing 9.